Elevated blood pressure has been established as an important risk factor for the development of cardiovascular disease, morbidity and mortality. The major manifestations of end-organ pathology associated with hypertension include congestive heart failure, ischemic heart disease, stroke, and peripheral artery disease, including renal failure and retinopathy. As blood pressure has been studied in children, it has become evident that adult essential hypertension and its complications may have origins in adolescence and childhood. Clinical observations have shown that some individuals with elevated blood pressure will develop one form of morbidity, while others develop a different form, and still others do not develop any complications. The reasons for this are unknown. Few studies have been done which attempt to delineate risk factors for the development of the different end-organ pathologies in hypertensive individuals. Two end-organ problems are particularly amenable to study in children. Ultrasound examination of the heart allows the non-invasive study of left ventricular hypertrophy which is an important precursor to the development of congestive heart failure. Retinal examination by fundal photograph and fluorescein angiography allows the examination of the effects of elevated blood pressure on the vessels of the eye. The purpose of the proposed investigation is to 1) describe the distribution of left ventricular hypertrophy and retinal vascular abnormalities in a population of children aged five to 20 years with essential hypertension; 2) evaluate potential risk factors for the development of these end-organ complications in this population; 3) test the hypothesis that the risk factors have an antecedent-consequence relationship with the complications; and 4) compare the risk factors for the development of left ventricular hypertrophy and retinal vascular disease. The research plan consists of two phases. The first phase is designed to use cross-sectional and case-control methodology to evaluate a number of potential risk factors for these complications. The second phase will investigate the development of left ventricular hypertrophy, changes in left ventricular function and retinal vascular disease, and the temporal relationship of these complications to the risk factors found to be important in the first phase, using a cohort design. The long-term objective of this research is to construct a causal model for the development of these end-organ complications.